Some XM-L questions

Sorry if any of those where answered in the existing threads, I got a bit flashlight-detached recently.

1. I need a replacement for a fried R2 emitter (sku.24200) - is an XM-L on a star (sku.51989) a straightforward replacement? (Is the R2 driver enough/any good?) Soldering is not a problem - is it better/cheaper to get an unsoldered emitter?

2. I'm thinking of modding Skylines I and II, to finally give them the oomph they lack. Is changing just the emitter to XM-L enough, or is it better to swap the driver too? I guess the latter, as they already have a good LED (R2) which is not bright - so bad driver.

3. Is it possible to use XM-L to make a >500 lumen 10440 keychain or a silly zoomable projector lightsaber? How big an issue is the heat?

Good questions. Here's what I've gathered...

1. I need a replacement for a fried R2 emitter (sku.24200) - is an XM-L on a star (sku.51989) a straightforward replacement? (Is the R2 driver enough/any good?) Soldering is not a problem - is it better/cheaper to get an unsoldered emitter?

A: A 20mm star will not fit that host, but sku 50599 should fit. The driver you currently have is only putting out 1000ma max (theoretically), and won't come close to driving an XM-L to its full potential. It's usually cheaper to buy the bare emitter if you don't mind reflowing it onto your current base. You will also run into fitment issue with your reflector and would have to enlarge the hole slightly to fit an XM-L.

2. I'm thinking of modding Skylines I and II, to finally give them the oomph they lack. Is changing just the emitter to XM-L enough, or is it better to swap the driver too? I guess the latter, as they already have a good LED (R2) which is not bright - so bad driver.

A: Keep in mind that the XM-L die size is bigger than the R2. As the skylines are throwers, your throw would suffer and most likely have a horrible ringy beam if you kept the same reflectors. For that size and style of light, the R2 is currently the best emitter for throw. I would look into upgrading the drivers.

3. Is it possible to use XM-L to make a >500 lumen 10440 keychain or a silly zoomable projector lightsaber? How big an issue is the heat?

A: Possible? Short answer, no. Long answer, maybe. Here's why: In order to get >500lm out of an XM-L, you will need at least 2amps. Even with an IMR 10440 you're looking at an almost 6C discharge of that cell, not to mention the non-existent heatsinking. I don't know of anyone who has or is willing to try that in something so small. You'd be safer and have longer runtime with a flash-bang grenade. As for a silly zoomable projector lightsaber, I can only assume you mean a flood to throw or a pure aspheric. Depending on the host and heatsinking, there should be no problem with that. Folks have been using the SST-50's with a big aspheric for quite awhile.

Hope that helps,

-Match

1. get the XML in 16mm star ( http://www.dealextreme.com/details.dx/sku.50599~r.43033281 ) and replace the old star with this. The stock driver will deliver only about 1Amp, so probably you should get the kaidomain 2,8A nanjg 105.

2. Stock driver of skyline only delivers about 1A (I beleive) so XM-L at 1Amp produces less light than a xpg-r5 at 1A (not so good mod)

3. Forget it. 10440 can not deliver the current neccesary to do that.

The hole in a reflector for an XR-E is pretty big and should work fine with a XM-L. Even at 1A, the XM-L is going to give off more light than the R2. A T6 binned XM-L is roughly equivalent to a S4. But you won't get anything like the throw that you had with the XR-E.

2. Stock driver of skyline only delivers about 1A (I beleive) so XM-L at 1Amp produces less light than a xpg-r5 at 1A (not so good mod)

Assuming this is remotely correct...

Cree XP-G brightness at 1A

R2 285-305 lm @ 1A
R3 305-325 lm @ 1A
R4 325-348 lm @ 1A
R5 348-370 lm @ 1A
S2 370-390 lm @ 1A
S3 390-410 lm @ 1A*
S4 410-430 lm @ 1A


Cree XP-G brightness at 1.5A

R2 380-406 lm @ 1.5A
R3 406-433 lm @ 1.5A
R4 433-463 lm @ 1.5A
R5 463-493 lm @ 1.5A
S2 493-520 lm @ 1.5A
S3 520-547 lm @ 1.5A*
S4 547-573 lm @ 1.5A

Cree XM-L brightness at 700mA

T5 260-280 lm @ 700mA
T6 280-300 lm @ 700mA*
U2 300-320 lm @ 700mA
U3 320-340 lm @ 700mA


Cree XM-L brightness at 1.5A

T5 504-543 lm @ 1.5A
T6 543-582 lm @ 1.5A*
U2 582-621 lm @ 1.5A
U3 621-660 lm @ 1.5A

... the R5 vs XM-L claim is not very accurate. If the lumen increase is close to linear... XM-L should be a bit better than R5 at all currents (if permitted)

Yes, but will be some "not good idea" to keep working an XML at only 1A. A 2,8Amp driver is only 4,7 USD

Thanks for answers, guys. Great info.

So:

1) I'm getting a T6 XM-L, an AR lens and a driver (which one? Stock R2 burnt with the stock driver, won't 2,8A make the led bien cuit instantly?)

2) I'm getting 2x Nanjg 105 for the Skylines and hope for the best with the swap (Old had quite a fight with that).

3) So maybe 14500? What about XM-L in something like Tank E07, or Romi G2? Or maybe there already is a mod like this?

By "silly zoomable lightsaber" of course I meant an XM-L aspheric, so Sipik, RC-29 or such.

you can use 14500 but must be IMR cells

1) I'm getting a T6 XM-L, an AR lens and a driver (which one? Stock R2 burnt with the stock driver, won't 2,8A make the led bien cuit instantly?)

- Not sure why your first lens/driver burnt up, but if it was from heat this'll only make it worse. Try to stay below 1.4a.

2) I'm getting 2x Nanjg 105 for the Skylines and hope for the best with the swap (Old had quite a fight with that).

-Use the Nanjg 105 for the xm-l, not the R2's that are in the skylines. Otherwise, you'll be in the same boat as you are with your other light. (poof)

3) So maybe 14500? What about XM-L in something like Tank E07, or Romi G2? Or maybe there already is a mod like this?

- Might work with an IMR14500 as a "Rodeo Light" (Good for 8 seconds at a time). Still have that heat issue to worry about...

-Match

I just stripped mine down. The infinitely variable output circuitry (aka. "variable pwm dimming") is in the tail and the regulator is in the head (based on lm393). The hardest thing is to get the old XR-E R2 star out since it is both protected by a press fit piece of plastic and is glued to the heat sink. The circuitry in the head was pretty easy to pull out, just use a pair of radio pliers and pull on the gold colored knob at the back of the head. It is a battery contact board and it should come off quite easily, mine is undamaged by the treatment.

The next part is to pull the inner board, the regulator, out of the head. The regulator is soldered to the brass sleeve which is in turn press fit into the head. Using the same radio pliers I gripped the big transistor and pulled both the regulator and brass sleeve straight out of the head. Expect this pulling to break the regulator, the big transistor (Q1) broke apart when I pulled at it.

As I said, getting the star off of the heat sink was the hardest part. I tried gripping it with the radio pliers but I would just pull pieces off of it. I heated the star using a blow torch in order to weaken the glue and after three rounds of heating I managed to grab a corner of the star with the pliers and peel it off of the heat sink.

The pwm dimming circuitry in the tail is easy to access using tweezers or needle nose pliers, I tested it with 2A and the switching transistor heated up a bit. I would not try it with 2.8-3A. Will have to put in a proper switch if I go for a 3A XM-L mod...

At 1A XM-L and XP-G give roughly the same light assuming the case at 25 C.

Doing some measures I realize the sad true which lie in the above sentence regarding the XP-G.You can not keep this little thing cold in a regular flashlight body at 1A ,let alone at 1,5A, there are many reports of failed apart emitters because heat.

Drived at 1,4 the case reach 80 C in few seconds even properly heatsinked in a mass of metal equivalent at the common torch.

In least than 4 minutes the ceramic substrate reach 87C which is 113C at the junction 80% of the claimed 25C output.The same test endure for an XR-E severely overdrived show 59C at the case 99c Tj ,87% output for an EZ1000.

Lets see how the XM-L behave heat related..

Don't forget here we are in summer and this is a worst scenario case, 28C ambient during the test